Workstation system and method for controlling a workstation system

ABSTRACT

A workstation system comprises a table, at least one electric drive arranged to adjust a height of the table, at least one depth sensor arranged on the table, the depth sensor being arranged to measure, in at least one point, a distance between the at least one depth sensor and a user of the workstation system located in front of the table, and at least one inclination sensor, in particular forming a physical unit with the at least one depth sensor, the inclination sensor being arranged to detect an angle of inclination of the depth sensor. The workstation system further comprises at least one evaluation unit arranged to evaluate a setting height of the table when the distance measured by the depth sensor falls below or exceeds a predefined value and to calculate and signal a height of the user based on the setting height and the inclination angle of the at least one inclination sensor if the current table height is not suitable for the height of the user.

This invention relates to a workstation system comprising a table and at least one electric drive arranged to adjust a height of the table. This invention further relates to a method for controlling such a workstation system.

In a workstation system with a height-adjustable table, a height of the table is adjusted to match a position (standing/sitting) of a user of the workstation system. In addition, the height of the table can be adjusted to match a user's height in each position. The user is often not aware of what an ergonomically suitable table height for his body height is.

An object of this invention is to describe a workstation system and a method for controlling a workstation system with which an ergonomically suitable table height can be determined for a user.

The above-mentioned object is solved with the system and method of the independent claims. Embodiments and further configurations of the invention are described in the dependent claims.

According to one embodiment, a workstation system comprises a table and at least one electric drive which is designed to adjust a height of the table. The workstation system further comprises at least one depth sensor, arranged on the table, the depth sensor being arranged to measure a distance in at least one point between the at least one depth sensor and a user of the workstation system, the user being located in front of the table. The workstation system further includes at least one inclination sensor that is arranged to detect an inclination angle of the depth sensor. Preferably, the at least one inclination sensor forms a physical unit with the at least one depth sensor. The workstation system further comprises at least one evaluation unit, which is arranged to evaluate a setting height of the table when the distance measured by the depth sensor falls below or exceeds a predefined value. The evaluation unit is further arranged to calculate and indicate a height of the user based on the setting height of the table and the angle of inclination of the at least one inclination sensor if the current table height is not suitable for the height of the user.

Such installation makes it possible to determine a height of the user with common, inexpensive depth sensors. Sensors that measure a distance using the time of flight (TOF) method are, for example, particularly suitable. Alternative distance meters, for example based on ultrasonic measurement methods, may of course also be used. No complex and expensive sensors are required. Furthermore, the height of any user can be determined in this way without a user having to register and/or enter body data into the workstation system. The height of the user can be calculated without efforts for the user each time the user changes from a seated to a standing position at the table. For example, the highest point of the user's header can be used as the user's height. The inclination sensor, which forms a physical unit with the depth sensor, makes it possible to correct the distance measured by the depth sensor and/or to correct the calculated height of the user if the measured or calculated values are corrupted due to an inclination of the depth sensor.

In at least one embodiment, the evaluation unit is further arranged to trigger the calculation of the height of the user depending on an adjustment of the height of the table.

In at least one embodiment, the workstation system comprises a presence sensor which is arranged to detect a presence of the user at the workstation system. In this way, the system for determining the height of the user can always then be active when the workstation system detects a presence of the user. A motion detector or a wearable that detects the presence of the user is suitable as a presence sensor, for example. The presence sensor can also trigger other actions of the workstation system. For example, when the user arrives, switching on a light, activating a socket, signalling a welcome message and/or connecting a wearable, smart device or similar to the workstation system. Such actions can be reversed, for example, when the workstation system detects that the user leaves.

In at least one embodiment, the workstation system further comprises a work chair, the work chair having at least one sensor arranged to detect a seated position of the user. In this way, the height of the table can be adjusted automatically and/or the user can be asked whether the height of the table should be adjusted automatically whenever a change in position of the user is detected. Especially in combination with the presence sensor, the workstation system can detect whether the user is in a seated or standing position, has changed position (e.g. from sitting to standing or from standing to sitting) or has left the workstation system.

In at least one embodiment, the workstation system also comprises a control unit which is arranged to generate a control signal for height adjustment of the table. The control signal is used to control the at least one electric drive. The user can actuate the control unit when it is indicated that the current table height is not suitable for his size.

In at least one embodiment, the control unit is arranged to generate the control signal for height adjustment of the table, based on a suitable table height calculated by the at least one evaluation unit. In this way, the table height is automatically adjusted to an ergonomically suitable height, if necessary upon confirmation of a request, if the current table height is not suitable for the height of the user.

In at least one embodiment, the workstation system also comprises an input unit via which the user of the workstation system can make at least one of the following inputs: Signalling a presence of the user, signalling whether the user is sitting or standing, initiating the height detection of the user, or adjusting the table height to the suitable table height calculated by the workstation system. In this way, a presence of the user and/or a position of the user can be signalled, even if the corresponding sensors are defective or not present. It is also possible to manually start the calculation of the user's height described above. Furthermore, when a table height not suitable for the height of the user is indicated, the table height can be manually adjusted by the user.

In at least one embodiment, the evaluation unit comprises a non-volatile memory on which a table for assigning a suitable table height to a calculated height of the user is stored. In this way, a simple correlation between the calculated height of the user and the ergonomically suitable table height can be established. User-specific data is not required in this embodiment. It is sufficient to provide data on the non-volatile memory according to ergonomic standards. In particular, different tables for standing and sitting positions can be stored. As an alternative to a table, the evaluation unit can also calculate the suitable table height. A combination of table data with a calculation by the evaluation unit for the suitable table height is also possible.

In at least one embodiment, the workstation system also comprises a display unit which is designed to indicate to the user an unsuitable table height detected by the evaluation unit. Such a display unit can be, for example, an optical display on the input unit. Alternatively, an acoustic signal or a haptic signal, for example a vibration of the display unit or another part of the workstation system, can indicate an unsuitable table height. Furthermore, it is possible to display an unsuitable table height detected by the evaluation unit on a computer screen, for example.

In at least one embodiment, the workstation system further comprises a monitor, wherein the depth sensor and the inclination sensor are mounted on the monitor and the evaluation unit calculates the height of the user based on the setting height of the table, the angle of inclination and a height of the monitor. The height of the monitor can be fixed, but it is also possible that the monitor is manually or electrically adjustable. In this way, the height of the user can be calculated by adjusting the height of the table and/or by adjusting the height of the monitor.

In at least one embodiment, the table includes a table top. The at least one depth sensor and the inclination sensor are arranged at one of the following locations: on a surface of the table top, integrated in the surface of the table top, on a bottom side of the table top, or on a side of the table top. Especially when the depth sensor and inclination sensor are integrated in the table top, the depth sensor and inclination sensor are inclined upwards. The correct height is then calculated by the inclination angle determined by the inclination sensor.

In at least one embodiment, the workstation system comprises a sensor holder arranged on the table. The at least one depth sensor and the inclination sensor are mounted on the sensor holder.

In at least one embodiment, the workstation system further comprises at least one further depth sensor which is designed to measure a mounting height of the physical unit. For example, the mounting height can represent the height of the physical unit above the table top, the physical unit consisting of depth sensor for measuring the user's distance and inclination sensor. Alternatively, the at least one additional depth sensor can also be used to measure an absolute height of the physical unit above a floor on which the table stands. The latter is particularly useful if the physical unit is mounted, for example, on a bottom side of the table top.

According to a second aspect, the above-mentioned object is solved by a method for controlling a workstation system which is described above. The workstation system further has at least one depth sensor arranged on the table, at least one inclination sensor forming a physical unit with the depth sensor and at least one evaluation unit. The method comprises the steps:

-   -   adjusting a height of the table by the at least one electric         drive,     -   measuring a distance with the depth sensor in at least one point         between the at least one depth sensor and a user of the         workstation system in front of the table while the height of the         table is being adjusted,     -   detecting an inclination angle of the depth sensor with the         inclination sensor,     -   calculating a height of the user with the evaluation unit when         the distance measured by the depth sensor falls below or exceeds         a predefined value, wherein the calculation is based on a         setting height of the table and the angle of inclination of the         depth sensor,     -   signalling a currently unsuitable table height based on the         calculated height of the user.

In at least one embodiment of the method, the adjustment of the height of the table and the measurement of the height of the user is automatically started when a presence of the user is registered for the first time within a predetermined period. In this way it is possible to automatically adjust the table and measure the height of the user only once during the predetermined period. In this way, even after a brief absence of the user, a re-registered presence does not result in the height of the table being adjusted and the height of the user being measured. If this is done too often, it would be disturbing for the user.

In at least one embodiment of the method, the adjustment of the height of the table and the measurement of the height of the user is automatically started when a change of a position of the user from a sitting to a standing position and/or from a standing to a sitting position is detected.

The embodiments of the method described herein are particularly suitable for controlling the embodiments of the workstation system described above.

Further advantageous embodiments are described in the attached claims and the following description of exemplary embodiments with respect to the attached figures. In the figures, the same reference signs are used for elements with essentially the same function, but these elements do not have to be identical in all details.

In the figures:

FIG. 1 shows a schematic drawing of a workstation system in a first state,

FIG. 2 shows a schematic drawing of the workstation system according to FIG. 1 in a second state,

FIG. 3 shows a side view of a workstation system for a seated user,

FIG. 4 shows a side view of the workstation system according to FIG. 3 for a standing user,

FIG. 5 shows a top view of a workstation system,

FIG. 6 shows an exploded view of a sensor.

FIGS. 1 and 2 show a schematic drawing of a workstation system 1 in two different states A, B. Both figures show a table 2 with a table top 3 and a table leg 4. The table leg 4 is in both figures height-adjustable. For this purpose, the table leg 4 contains a control unit and an electric drive, which, however, are not visible in the figures. A user 5 of the workstation system 1 sits at table 2 and a depth sensor 6 is arranged at an upper side of table top 3, the upper side facing away from table leg 4. According to the exemplary embodiment of FIGS. 1 and 2, the depth sensor 6 is not mounted directly on the table top 3, but a some distance above the table top 3. For example, the depth sensor 6 can be mounted on a monitor standing on the table top 3 or on a sensor holder provided especially for the depth sensor 6. Alternatively, the depth sensor 6 can of course also be mounted directly on top, on a side or underneath the table top 3.

In both figures, table 2 is set to a height ht, ht′, which relates to a height of the table top above a floor on which table 2 stands. A height hu, hu′ of user 5 represents in both figures the height of an upper end of a head of user 5 above the ground. In states A and B, the heights ht and ht′ respectively hu and hu′ are each identical. However, a height hs, hs′ of the depth sensor 6 above the table top 3 differs in the states A and B.

In state A, the height ht of table top 3 and the height hs of depth sensor 6 are set so that together they constitute the height hu of user 5. Furthermore, in state A, the depth sensor 6 is horizontally aligned so that it measures a distance d along a horizontal line parallel to the surface of the table top 3 between the depth sensor 6 and an object in front of the depth sensor 6. FIG. 1 shows state A, where the height ht of table 2 together with the height hs of depth sensor 6 constitute the height hu of user 5. This results in the height ratio hu=hs+ht. In this state A, the depth sensor 6 measures the distance d between the depth sensor 6 and the highest point of the user's 5 head.

If the height hs and/or the height ht is increased in state A, the measurement of depth sensor 6 no longer detects user 5 but an object lying behind user 5, for example a wall. This results in a significant increase in the distance measured by the depth sensor 6. In this exemplary embodiment, the depth sensor 6 measures the distance d several times per second during a movement of the table 2. The measurements result in a depth profile, e.g. if the table is moved upwards from a chest height of the user 5. If a depth difference between measured distances d of, for example, more than 30 cm is registered within a height difference of 2 cm, the highest point of the user's head 5 is reached and exceeded.

Alternatively, the significant increase could be registered, for example, as an exceeding of a predetermined absolute threshold. Said threshold may be in the range of typical distances from a user 5 to a monitor, especially when the depth sensor 6 is mounted on such a monitor. Depending on the size of the monitor, for example, this range can be between 50 cm and 80 cm. Another possibility would be to evaluate a significant deviation from a moving average of the measured distance values d as a significant increase.

Workstation system 1 comprises an evaluation unit, which is not shown in FIGS. 1 and 2. The evaluation unit detects the significant increase of the measured distance d and can thus calculate the height hu of user 5 based on the height ht of table 2 and the height hs of depth sensor 6.

For example, the evaluation unit has a non-volatile memory on which a table is stored. The table comprises a database with standardized body relations and corresponding ergonomically suitable heights ht, hs. With this table, ergonomically suitable heights ht, hs for table 2 and for the depth sensor 6 can be assigned to the calculated heights hu of user 5. In addition, the database can also be configured with user-specific body relations and the data set, which is relevant for the user, can be selected via a user identification. If, after comparing the table with the calculated height hu of user 5, the evaluation unit detects that the current height ht, hs of table 2 and/or the depth sensor 6, for example if depth sensor 6 is mounted on a monitor, is not ergonomically suitable, the evaluation unit can signal this to user 5. This can be done, for example, via a display that is specially mounted for this purpose on the workstation system 1, via a monitor or via an acoustic or haptic signal. User 5 can then manually adjust the height ht and/or the height hs via an input unit or give a command to workstation system 1 to set said heights ht, hs automatically to ergonomically suitable values. As an alternative to using a table, suitable heights ht, hs can also be calculated by the evaluation unit.

In state B, the height hs′ of the depth sensor 6 is greater than the height hs in state A. In addition, the depth sensor 6 is not aligned horizontally, but tilted downwards in the direction of the table top 3 by an angle ‘a’ with respect to the horizontal alignment. This may be the case, for example, if the depth sensor 6 is mounted on a monitor, the monitor has been moved upwards and tilted downwards. Inclination of the depth sensor 6 means that, in state B, the height hu′ of the user is no longer equal to the sum of heights hs′ and ht′. To detect and correct this difference, an inclination sensor 7 is attached to the depth sensor 6. Depth sensor 6 and inclination sensor 7 form a physical unit, i.e. they are connected in such a way that if the depth sensor 6 is tilted, the inclination sensor 7 is tilted by the same angle as well. For example, the inclination sensor 7 is mounted on the depth sensor 6 or both sensors 6, 7 are mounted on a common board. The angle ‘a’ can be determined with the inclination sensor 7.

In the case of state B, if the evaluation unit registers the significant increase in distance d′, the equation hu′+hk=hs′+ht′ applies. The values hs′ and ht′ are known to the evaluation unit from the setting heights of table 2 and a mounting height of the depth sensor 6 above table top 3. Alternatively or additionally, another depth sensor, not shown in FIGS. 1 and 2, can be attached to the physical unit consisting of depth sensor 6 and inclination sensor 7, which in this case measures the value hs′. Such an additional depth sensor can be attached to the physical unit and point downwards towards the table top, thus measuring the height of the physical unit above the table top 3.

From the angle ‘a’ and the measured distance d′, at the moment when the significant increase is detected, the correction height hk can then be determined. This can be subtracted from the sum hs′+ht′ so that the correct height hu′ can be determined. If the depth sensor 6 were tilted away from the table top 3 and would point upwards, this would also be detected by the inclination sensor 7 and the correction height hk would be added to the sum hs′+ht′. Based on the determined height hu′ of user 5, ergonomically unsuitable heights hs′ or ht′ can be signalled to user 5 according to state A.

The tilting also results in the distance d′ measured by the depth sensor 6 being greater than the distance d measured in state A. In this exemplary embodiment, as described above, the significant increase in the measured distance d is registered by evaluating the depth difference of the measured distance values d for a certain height difference. In this case, no absolute distance is evaluated. This means that the corruption of distance d, shown in state B, does not have to be corrected. However, it would be possible to calculate the distance d from the distance d′, measured in state B, using the determined angle ‘a’. This would be particularly advantageous if a comparison of the absolute measured distance with an absolute threshold is compared in order to determine the significant increase in distance d. As an alternative to correcting the measured distance d′, for such an evaluation, also a sufficiently high predetermined threshold can be selected, so that the correction of the distance d′, which is usually in the range of a few centimetres, becomes obsolete.

FIGS. 3 and 4 show side views of a workstation system 1 for a seated user 5 in FIG. 3 and for a standing user 5 in FIG. 4. The embodiment of workstation system 1 of FIGS. 3 and 4 essentially corresponds to the embodiment of workstation system 1 of FIGS. 1 and 2. In FIGS. 3 and 4, the physical unit of the depth sensor 6 and the inclination sensor 7 is located at an upper end of a monitor 8 which stands on the table top 3. In FIGS. 3 and 4, monitor 8 comprises a height-adjustable monitor stand 9 with an electric drive, so that the monitor stand 9 is electrically height-adjustable. For this purpose, for example, the monitor stand 9 contains a spindle drive. In addition to an ergonomically correct adjustment of the height ht″ of table 2, an ergonomically correct adjustment of the height hs″ of the depth sensor 6 on monitor 8 and thus of monitor 8 can be carried out.

FIG. 3 shows a state C after an ergonomic correction of the heights hs″ and ht″ has been carried out. In this state, for example, the top line of monitor 8 is approximately 15° below eye level of user 5. Forearms of user 5 lie loosely on table top 3 and upper arms and forearms form a right angle. Alternative specifications for setting ergonomically correct heights hs″ or ht″ are of course possible. In state C, shown in FIG. 3, user 5 sits on a work chair 10. Work chair 10 includes a sensor, for example a gas pressure spring 11, to register a pressure on the work chair 10. In this way, workstation system 1 can determine whether user 5 is sitting or standing at table 2. If the gas pressure spring 11 registers that user 5 is no longer seated at table 2 due to a drop in pressure on the work chair 10, the workstation system 1 changes to the state D shown in FIG. 4. This can be done automatically, for example, when user 5 confirms a query from workstation system 1, or by manual height adjustment by user 5. In addition, the work chair 10 can also be equipped with additional sensors, for example to evaluate the posture of user 5.

While the table top 3 is moved upwards by extending the table legs 4, the user 5 stands in front of the table 2. The monitor stand 9 is also extended in the exemplary embodiment described herein. Alternatively, a height adjustment of monitor 8 can also be carried out after moving the table 2. Of course, it is also possible to maintain a height of the monitor 8. The depth sensor 6 measures a distance d between the depth sensor 6 and the user 5 while the table legs 4 are extended. The distance d is measured according to the example described with respect to FIGS. 1 and 2. When the heights ht″, hs″ of table 2 and depth sensor 6 reach the state D shown in FIG. 4, a significant increase in distance d is measured by depth sensor 6 and, as described with reference to FIGS. 1 and 2, detected by an evaluation unit. The height hu′″ of user 5 is thus calculated in state D as the sum hs′″+ht′″. The evaluation unit derives the heights hs′″ and ht′″ from the setting heights of the table legs 4 and the monitor stand 9.

As described with respect to FIG. 3, for an ergonomically appropriate height ht′″ of table 2 or for an ergonomically appropriate height of monitor 8, for example, the top line of monitor 8 is approximately 15° below the eye level of user 5 and it is also possible for user 5 to place the forearms loosely on table top 3 so that upper arm and forearm form a right angle. From the calculated height hu′″ of user 5, the evaluation unit derives ergonomically suitable heights ht′″, hs′″ for table top 3 and for monitor 8 from a table. This table is stored, for example, on a non-volatile memory of the evaluation unit. The height ht′″ of table top 3 is thus already set to an ergonomically suitable height in FIG. 4. However, the height hs′″ of monitor 8 is detected as too high in state D by an evaluation unit arranged in workstation system 1, based on height specifications from the table. For example, the evaluation unit can then signal to user 5 via monitor 8 that the adjusted height hs′″ of monitor 8 is not suitable. User 5 can then set an ergonomically suitable height hs′″ of monitor 8 using the options described above.

In the event that the height ht′″ of the table top 3 were also not ergonomically suitable, this could be indicated to the user 5 via a display unit 12, which is attached to a bottom side of the table top 3. As an alternative to the embodiment described above, this display unit 12 can also display an unsuitable height hs′″ of monitor 8 to user 5. In addition to display unit 12, an input unit 13 is located on the bottom side of table top 3, via which the user 5 can adjust the height ht′″, hs′″ of table 2 respectively monitor 8 with or without request from the evaluation unit.

As an alternative to the adjustment described here, the height hu′″ of the user can also be determined when the table legs 4 and/or the monitor stand 9 are retracted. In this case, for example when a transition from a standing to a sitting position of user 5 is detected, the depth sensor 6 measures a distance d while moving the table top 3 and/or monitor 8, the distance d corresponding to a distance of the depth sensor from an object located behind the user 5, for example a wall. If then the measuring point of the depth sensor 6 hits the highest point of the head of user 5, a significant drop in the measured distance d is registered. The evaluation is performed complementary to the evaluation described above when the table 2 is extended. In this case a depth difference of e.g. more than 30 cm for a certain height difference, e.g. 2 cm, is recorded. Also this way, the height hu′″ of user 5 can be determined.

The checking of the adjusted height h′″, hs′″ of table top 3 and/or monitor 8 described herein can, for example, always be carried out when a user 5 is detected by a presence sensor at workstation system 1 and/or when a change from a standing to a seated position of user 5 or vice versa is detected. In addition, it is possible to move the height h′″, hs′″ of table top 3 and/or monitor 8 to a resting position if no user 5 is detected at workstation system 1, or an absence has been detected for a certain time. It is also possible to determine the height hu′″ of user 5 not always by moving the entire table 2, but to determine the height hu′″ of user 5 only by moving the monitor stand 9. Even without moving table 2, the evaluation unit can then check the setting height of table 2 and thus detect and, if necessary, signal an unsuitable height ht′″ of table 2.

In this embodiment, the height of user 5 is only measured when changing from a standing to a sitting position, or vice versa. If height adjustment is carried out within a position (standing or sitting), for example a height correction of only a few centimetres, this is done without measuring the height of the user 5. This saves unnecessary moving of table 2.

FIG. 5 shows a top view of a workstation system 1. The features shown in FIG. 5 can be combined as desired with the exemplary embodiments of the previous figures. FIG. 5 shows a table 2 of workstation system 1 from above, so that an upper side of a table top 3 of table 2 can be seen. On one side of table 2 there is a user 5 of workstation system 1. On table top 3 there is a monitor 8, which faces a direction of user 5. The monitor 8 is mounted to a monitor stand 9. On an upper side of monitor 8, the upper side facing away from table top 3, a depth sensor 6 is located. This depth sensor 6 forms, as in the previous embodiments, a physical unit with an inclination sensor 7.

In this exemplary embodiment, the depth sensor 6 measures a distance d between depth sensor 6 and user 5 with two measuring ranges M1, M2, each with an aperture angle ‘b’. For example, the depth sensor 6 has two TOF (Time of Flight) sensors 14, which determine a distance using an optical time of flight measurement. The measuring ranges M1, M2 extend two-dimensionally in the drawing plane of FIG. 5 and overlap at least partially, so that the distance d is measured from both TOF sensors 14 in a measuring range M3. In this case, for example, it is possible to only evaluate the values measured by the two TOF sensors 14 if they have a plausible match.

FIG. 5 shows the measuring ranges M1, M2 of two parallel aligned TOF sensors 14 mounted at a distance x from each other. For example, each TOF sensor 14 has an aperture angle of 25°. Assuming a distance d=80 cm, a distance x=3.5 cm and a width y of the measuring range M3 at the distance d of y=54 cm, the angle by which the TOF sensors are rotated relative to each other is ±12.155°. The width y of the measuring range M3 is based on statistical standard data which indicate that a human head is typically 18 cm wide and the body in the shoulder area is about three times as wide as the head. Width y of the measuring range M3 was selected here as the shoulder width (corresponding approximately to a person's width) of a person in order to ensure an appropriate tolerance range for the measurement of the height of user 5. This width y is suitable, since a wider measuring range M3 leads, for example, to erroneous measurements if there are several persons at the workstation system and a smaller width y would not offer a tolerance range, so that the user would have to remain very precisely and still in the measuring range M3 during the height measurement. However, values other than those given here are of course possible. The distance d measured in the measuring range M3, is processed according to the embodiments of to the previous figures.

The TOF sensors 14 shown in FIG. 5 not only scan a line, as described in FIGS. 1-4, but scan a field to measure the distance d during a movement of table 2 and/or monitor 8. Alternatively, sensors can be used that already scan a field, while table 2 and monitor 8 are not moved. However, this requires more complex sensors.

FIG. 6 shows an example of a physical unit of a depth sensor 6 with an inclination sensor 7 in an exploded view. This unit can be used for all exemplary embodiments of the previous figures. The unit comprises an upper part 15 of a housing and a lower part 16 of the housing that can be inserted into part 15. The lower part 16 of the housing is shaped so that it can be slid onto an upper side of a monitor. The lower part 16 is interchangeable so that suitable shapes of different monitor shapes can be selected without having to replace the entire unit.

Inside the upper part 15 of the housing, a board 17 is arranged. The board 17 is held by bars 18 on an inner side of the upper part 15 of the housing. The board 17 has a USB connector 19 at one end. The physical unit of sensors 6, 7 can be connected to an evaluation unit of a workstation system via this USB connector 19. However, USB connector 19 is optional. Alternatively, the physical unit of sensors 6, 7 can also be connected to the evaluation unit without cables. In a front area of the upper part 15 of the housing, two TOF sensors 14 are arranged behind a pane, in which two openings 21 are located. The TOF sensors 14 are connected to the board 17 via flexible cables 22. The TOF sensors 14 are aligned so that they lie behind the openings 21. The openings 21 are covered by transparent windows 23 to protect the TOF sensors. An inclination sensor 7, which is not visible in this figure, is mounted on the back of board 17 and can be used to detect an inclination of the entire physical unit. In addition, a presence sensor can be installed in the physical unit shown here, which registers a presence of a user.

VCSEL (Vertical Cavity Surface-Emitting Laser) are used in this exemplary embodiment as TOF sensors 14. Such TOF sensors 14 are relatively inexpensive and suitable for this application as the emitted signals are invisible to the human eye and therefore do not pose a risk to a user. Furthermore, such TOF sensors 14 have a sufficient range, high immunity to ambient light and sufficient robustness to optical crosstalk with the windows 23.

As an alternative to the TOF sensors mentioned here, sensors can also be used, which measure the distance d with an entire field of measuring points. 

1. A workstation system comprising a table, at least one electric drive arranged to adjust a height of the table, at least one depth sensor arranged on the table, the depth sensor being arranged to measure in at least one point a distance between the at least one depth sensor and a user of the workstation system located in front of the table, at least one inclination sensor, in particular forming a physical unit with the at least one depth sensor, the inclination sensor being arranged to detect an inclination angle of the depth sensor and at least one evaluation unit, arranged to evaluate a setting height of the table when the distance measured by the depth sensor falls below or exceeds a predefined value and to calculate and signal a height of the user based on the setting height and the inclination angle of the at least one inclination sensor if the current table height is not suitable for the height of the user.
 2. The workstation system according to claim 1, wherein the evaluation unit further is arranged to trigger the calculation of the height of the user depending on an adjustment of the height of the table.
 3. The workstation system according to claim 1, further comprising a presence sensor, arranged to detect a presence of the user at the workstation system.
 4. The workstation system according to claim 1, further comprising a work chair, wherein the work chair has at least one sensor adapted to detect a seated position of the user.
 5. The workstation system according to claim 1, further comprising a control unit, arranged to generate a control signal for height adjustment of the table.
 6. The workstation system according to claim 5, wherein the control unit is arranged to generate the control signal for height adjustment of the table based on a suitable table height calculated by the at least one evaluation unit.
 7. The workstation system according to claim 1, further comprising an input unit via which the user of the workstation system can make at least one of the following inputs: signalling a presence of the user, indicating whether the user is sitting or standing, starting the height detection of the user, adjusting the table height to the suitable table height calculated by the workstation system.
 8. The workstation system according to claim 1, wherein the evaluation unit comprises a non-volatile memory on which a table for assigning a suitable table height to a calculated height of the user is stored.
 9. The workstation system according to claim 1, further comprising a display unit arranged to indicate to the user of the workstation system an unsuitable table height detected by the evaluation unit.
 10. The workstation system according to claim 1, further comprising a monitor, wherein the depth sensor and the inclination sensor are mounted on the monitor and the evaluation unit calculates the height of the user based on the setting height of the table, the inclination angle and a setting height of the monitor.
 11. The workstation system according to claim 1, wherein the table comprises a table top and the at least one depth sensor and the inclination sensor are arranged at one of the following locations: on top of a surface of the table top, integrated in the surface of the table top, on a bottom side of the table top, or on a side of the table top.
 12. The workstation system according to claim 1, further comprising a sensor holder arranged on the table, wherein the at least one depth sensor and the inclination sensor are mounted on the sensor holder.
 13. The workstation system according to claim 1, further comprising at least one further depth sensor adapted to measure a mounting height of the physical unit.
 14. Method for controlling a workstation system comprising a table, at least one electric drive, at least one depth sensor arranged on the table, at least one inclination sensor forming a physical unit with the depth sensor, the method comprising: adjusting, by the at least one electric drive, a height of the table; measuring, with the depth sensor, a distance in at least one point between the at least one depth sensor and a user of the workstation system located in front of the table while the height of the table is adjusted; detecting, with the inclination sensor, an inclination angle of the depth sensor; calculating a height of the user when the distance, measured by the depth sensor, falls below or exceeds a predefined value, wherein the calculation is based on a setting height of the table and the angle of inclination of the depth sensor; signalling a currently unsuitable table height based on the calculated height of the user.
 15. The method for controlling a workstation system according to claim 14, wherein adjusting the height of the table and measuring the height of the user is automatically started when a presence of the user is first registered during a predetermined time period.
 16. The method for controlling a workstation system according to claim 14, wherein the adjustment of the height of the table and the measurement of the height of the user is automatically started when a change of a position of the user from a sitting to a standing position and/or from a standing to a sitting position is detected. 